JP2011090862A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell system which can prevent breakage of a fuel cell and a hydrogen generator, even if an exhaust port is closed when the exhaust port of the fuel cell system is closed, since the internal pressure of the hydrogen generator and the fuel cell would increase and cause their breakage. <P>SOLUTION: The fuel cell system 1 is provided with a fuel cell 2, a hydrogen generator 3, a water tank 6 and an exhaust port 7. The water tank 6 is provided with a barrier rib 16 for dividing the tank into a first water storage section 17 and a second water storage section 18; a communication section which can communicate water stored in the first water storage section 17 and the second water storage section 18; and a drain port 20, arranged at a position which is higher than the water level of the first water storage part 17 and higher than the communication section and is formed in the second water storage section 18; and thereby when the exhaust port is closed, the exhaust gas is discharged from the drain port 20 via the first passage 8 to the second passage 12 and the first water storage section 17 and the second water storage section 18, and breakage of the fuel cell 2 and the hydrogen generator 3 is prevented. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel cell system including an exhaust passage for exhausting exhaust gas generated during operation of the fuel cell system and a water storage unit for storing water contained in the exhaust gas.

  A fuel cell is a device that generates water and heat by generating electricity through an electrochemical reaction between a fuel gas containing hydrogen and an oxidant gas containing oxygen. Fuel cells have high power generation efficiency because they can be directly extracted as electrical energy without converting the chemical energy of the fuel into mechanical energy.

  There exists a thing represented by patent document 1 as a conventional common fuel cell system.

  FIG. 7 shows a conventional fuel cell system described in Patent Document 1. In FIG. As shown in FIG. 7, the fuel cell system 201 combusts a hydrogen generator 203 that generates fuel gas containing hydrogen to be supplied to the fuel cell 202 as fuel, and unreacted fuel gas discharged from the fuel cell. A combustor 203a of the hydrogen generator 203 to be reused, a raw material transmitter 204 for sending the raw material to the hydrogen generator, a flue gas heat exchanger 205 for removing moisture in the flue gas discharged from the combustor 203a, A water tank 206 that stores water condensed by the combustion exhaust gas heat exchanger 205 and the like, a first exhaust path 208 that guides the combustion exhaust gas to the exhaust port 207, a branch from the first exhaust path 208, and communication with the water tank 206 for combustion A first condensate flow path 209 that guides water condensed in the exhaust gas heat exchanger 205 is provided, an air blower 210 that supplies an oxidant to the fuel cell 202, and the fuel cell 2 An oxidant exhaust gas heat exchanger 211 that removes moisture in the unreacted oxidant (hereinafter referred to as oxidant exhaust gas), a second exhaust path 212 that guides the oxidant exhaust gas to an exhaust port, and a second exhaust path The second condensate flow path 213 is branched from 212 and communicates with the water tank 206 to guide water condensed in the oxidant exhaust gas heat exchanger 211.

JP 2008-176999 A

  However, in the configuration of the conventional fuel cell system, when the exhaust port 207 is blocked, the stability of combustion in the combustor 203a may be impaired, and the internal pressure of the fuel cell 202 or the hydrogen generator 203 may be impaired. As a result, the fuel cell 202 and the hydrogen generator 203 may be damaged.

  Accordingly, the present invention solves the above-described conventional problems, and when the exhaust port is blocked, exhaust gas is discharged from the drain port of the water tank, thereby preventing an increase in the internal pressure of the hydrogen generator or the fuel cell. An object of the present invention is to provide a fuel cell system that prevents damage to a hydrogen generator or a fuel cell.

In order to achieve the above-described conventional problems, a fuel cell system of the present invention includes a hydrogen generator that generates hydrogen-containing fuel gas from a raw material and water by a reforming reaction, and an oxidant gas that includes fuel gas and oxygen. Included in the exhaust gas, a fuel cell for generating electricity using, an exhaust port for exhausting exhaust gas exhausted from at least one of the hydrogen generator and the fuel cell to the outside of the housing, a first flow path for guiding exhaust gas to the exhaust port, and The water tank includes a sealed water tank and a second flow path that branches off from the first flow path and guides water contained in the exhaust gas to the water tank. A partition wall that is divided into a water storage unit, a communication unit that communicates water stored in the first water storage unit and the second water storage unit, and a second flow path that communicates with the first water storage unit. The drain outlet is located higher than the lowest part of the partition wall and higher than the communication part. To configure.

  Thereby, even if the exhaust port is blocked, the exhaust gas is discharged from the drain port from the first channel through the second channel, the first water storage unit, and the second water storage unit.

  In the fuel cell system of the present invention, even if the exhaust port is blocked, exhaust gas can be discharged from the drain port of the water tank. Therefore, the internal pressure of the hydrogen generator and the fuel cell can be prevented from increasing, and the hydrogen generator and the fuel cell can be damaged. It can be prevented.

Schematic of the fuel cell system in Embodiment 1 of the present invention Schematic diagram showing the configuration of the water tank of the fuel cell system according to Embodiment 1 of the present invention. Schematic of the fuel cell system in Embodiment 2 of the present invention FIG. 5 is a characteristic diagram showing the feed rate and specified value of the raw material gas of the fuel cell system in Embodiment 2 of the present invention. Schematic of the fuel cell system in Embodiment 3 of the present invention FIG. 5 is a characteristic diagram showing the air delivery amount and specified value of the fuel cell system according to Embodiment 3 of the present invention. Schematic diagram of a conventional fuel cell system

  A first aspect of the present invention includes a hydrogen generator that generates a fuel gas containing hydrogen from a raw material and water by a reforming reaction, a fuel cell that generates power using an oxidant gas containing a fuel gas and oxygen, and a hydrogen generator And an exhaust port that exhausts exhaust gas exhausted from at least one of the fuel cells to the outside of the housing, a first flow path that guides the exhaust gas to the exhaust port, and water that is contained in the exhaust gas is stored and formed in a sealed housing The water tank is divided into a first water storage section and a second water storage section. The partition wall is divided into a first water storage section and a second water storage section. And a communication part for communicating the water stored in the first water storage part and the second water storage part, a second flow path is connected to the first water storage part, and a first water storage part is provided to the second water storage part By configuring a drain outlet that is higher than the water level and higher than the communication part, When closed, the pressure in the first reservoir increases, and the pressure in the first reservoir of the water tank communicating with the first and second channels also increases. It is pushed down to a position lower than the partition wall, the water surface of the second water reservoir rises to the drainage port or more, water is discharged from the drainage port, and the exhaust gas flows from the first channel to the second channel, the first water reservoir, and the second water reservoir. It can be discharged from the drainage port through the part, and damage to the fuel cell and the hydrogen generator can be prevented.

  In the second aspect of the present invention, in particular, the water tank of the first aspect of the present invention has a water level detector for detecting the water level, so that the operation is performed when the water level detector detects that the water level is lower than the specified value. By providing a control unit that controls to stop, when the exhaust port is blocked, the water level of the first reservoir is lowered, so the blockage of the exhaust port can be detected by the water level detector, The hydrogen generator can be prevented from being damaged.

In particular, the third aspect of the present invention includes a raw material supply unit that supplies a raw material to the hydrogen generator of the first aspect of the present invention, and a raw material flow rate measurement unit that measures a raw material supply amount supplied from the raw material supply unit. By further including a control unit that controls to stop the operation when the supply amount falls below a specified value, the pressure loss of the first flow path increases when the exhaust port is blocked, and the first flow path Since the raw material supply amount decreases due to an increase in the pressure loss, the blockage of the exhaust port can be detected due to the decrease in the raw material supply amount, and damage to the fuel cell and the hydrogen generator can be prevented.

  In particular, the fourth aspect of the present invention has a raw material supply part that supplies the raw material gas to the hydrogen generator of the first aspect of the present invention, and has detected that the supply capacity of the raw material supply part is higher than a specified value. Sometimes, by further providing a control unit that controls to stop the operation, when the exhaust port is closed, the pressure loss of the first flow path increases, and the supply of the raw material supply unit is increased by the increase of the pressure loss of the first flow path. Since the capacity is increased, it is possible to detect an exhaust port blockage and prevent damage to the fuel cell and the hydrogen generator.

  In particular, the fifth aspect of the present invention includes an air supply unit that supplies air to the fuel cell of the first aspect of the present invention, and an air flow rate measurement unit that measures the amount of air supplied from the air supply unit. By further including a control unit that controls to stop the operation when the amount falls below a specified value, the pressure loss of the first flow path increases when the exhaust port is blocked, and the pressure of the first flow path Since the amount of air supply decreases due to the increase in loss, the blockage of the exhaust port can be detected due to the decrease in the amount of air supply, and damage to the fuel cell can be prevented.

  The sixth aspect of the present invention has an air supply unit that supplies air to the fuel cell of the first aspect of the present invention, and operates when it is detected that the supply capability of the air supply unit is higher than a specified value. By further including a control unit that controls to stop the air flow, the pressure loss of the first flow path increases, and the supply capacity of the air supply unit increases due to the increase of the pressure loss of the first flow path. Can be detected, and damage to the fuel cell can be prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the present embodiment.

(Embodiment 1)
FIG. 1 is a schematic diagram showing a configuration of a fuel cell system according to Embodiment 1 of the present invention.

  In FIG. 1, a fuel cell system 1 according to the present embodiment includes a fuel cell 2 that generates power using a fuel gas containing hydrogen and an oxidant gas containing oxygen, and hydrogen by a reforming reaction from raw materials and water. Hydrogen generator 3 for generating fuel gas, raw material blower 4 as a raw material supply unit for supplying the raw material to hydrogen generator 3, and hydrogen generation for burning and reusing unreacted fuel gas discharged from fuel cell 2 A combustor 3a of the combustor 3, a combustion exhaust gas heat exchanger 5 for removing moisture in the combustion exhaust gas discharged from the combustor 3a, a water tank 6 for storing water condensed in the combustion exhaust gas heat exchanger 5 and the like, A first exhaust path 8 that leads to an exhaust port 7 that discharges combustion exhaust gas to the outside of the housing, and a first branch that branches from the first exhaust path 8 and communicates with the water tank 6 to guide water condensed in the combustion exhaust gas heat exchanger 5. A condensed water flow path 9 is provided. The air blower 10 serves as an air supply unit for supplying the oxidant gas to the fuel cell 2 and the oxidant exhaust gas heat for removing moisture in the unreacted oxidant gas (hereinafter referred to as oxidant exhaust gas) discharged from the fuel cell 2. An exchanger 11, a second exhaust passage 12 that guides the oxidant exhaust gas to the exhaust port 7, a second branch that branches from the second exhaust passage 12, communicates with the water tank 6, and guides the water condensed in the oxidant exhaust gas heat exchanger 11. 2 The water in the condensed water flow path 13 and the hot water storage tank 14 is circulated to condense the heat of condensation from the combustion exhaust gas heat exchanger 5 and the oxidant exhaust gas heat exchanger 11 and the cooling water heat (not shown) of the fuel cell 2 A hot water circulation path 15 configured to collect in the tank 14 is provided.

  The first exhaust path 8 and the second exhaust path 12 as constituent members in the present embodiment are specific examples of the first flow path of the first aspect of the present invention, and the first condensed water flow path 9 and the second condensed water flow. The path 13 is a specific example of the second flow path of the first present invention.

  A specific operation of the fuel cell system 1 in the present embodiment will be described.

  In the fuel cell system 1, raw materials such as natural gas and LPG are supplied to a hydrogen generator 3 by a raw material blower 4. In the hydrogen generator 3, the supplied raw material is steam reformed in a steam atmosphere, and a fuel gas containing a large amount of hydrogen is generated. The generated fuel gas is supplied to the fuel electrode side of the fuel cell 2. The air blower 10 supplies air as an oxidant gas to the oxidant electrode side of the fuel cell 2.

  In the fuel cell 2, the reaction is thus performed using the supplied fuel gas and oxidant gas, thereby generating power and generating heat. This heat is recovered in the cooling water flowing through the fuel cell 2.

  Here, unreacted fuel gas discharged from the fuel cell 2 without being used for the reaction is supplied to the combustor 3a of the hydrogen generator 3 and used for combustion. The reaction part (not shown) of the hydrogen generator 3 is heated by the combustion heat generated in the combustor 3a, whereby the steam reforming reaction is performed with the reaction part kept at a predetermined temperature. The flue gas discharged from the combustor 3 a is sent to the flue gas heat exchanger 5. In such a configuration, the heat of the combustion exhaust gas is recovered by the water in the hot water circulation path 15 and the combustion exhaust gas is cooled to a dew point temperature or less, thereby condensing the moisture of the combustion exhaust gas. The condensed water is stored in the water tank 6 through the first condensed water channel 9. Further, the gaseous component of the combustion exhaust gas is discharged to the outside from the exhaust port 7 through the first exhaust path 8.

  The unreacted oxidant exhaust gas discharged from the fuel cell 2 without being used for the reaction is sent to the oxidant exhaust gas heat exchanger 11. In such a configuration, the heat of the oxidant exhaust gas is recovered by the water in the hot water circulation path 15, and the oxidant exhaust gas is cooled to the dew point temperature or lower, thereby condensing the moisture of the oxidant exhaust gas. The condensed water is stored in the water tank 6 through the second condensed water channel 13. Further, the gaseous component of the oxidant exhaust gas is discharged to the outside from the exhaust port 7 through the second exhaust path 12.

  Next, a detailed configuration of the water tank 6 characterizing the present invention will be described with reference to FIG. As shown in FIG. 2, the water tank 6 is divided into a first water storage part 17 and a second water storage part 18 by providing a partition wall 16 as shown in FIG. A communication portion 6 </ b> A that communicates the water stored in the portion 17 and the second water storage portion 18 is formed. The water condensed in the combustion exhaust gas heat exchanger 5 and the oxidant exhaust gas heat exchanger 11 is stored in the first water storage unit 17 by guiding it through the first condensed water channel 9 and the second condensed water channel 13. Further, the water level detector 19 is provided at a position higher than the lowermost part 16 </ b> A of the partition wall 16 of the first water reservoir 17. The second water storage section 18 is provided with a drain outlet 20 at a position higher than the water level detector 19 so that the stored water is discharged. The height of the drain outlet 20 is such that the fuel cell 2 and hydrogen The height is set so that the exhaust gas can be discharged from the drain port 20 below the pressure resistance of the generator 3. Assuming that the height from the lowermost part 16A of the partition wall 16 to the drain outlet 20 is Hmm, the pressure resistance of the hydrogen generator 3 is lower than the pressure resistance of the fuel cell 2, and the pressure resistance of the hydrogen generator 3 is AkPa, from the lowermost part 16A of the partition wall 16 The height H to the drain port 20 is 103 × A mm or less. If the water level detector 19 of the first water storage unit 17 detects a drop in the water level when the fuel cell system 1 is started, the water supply valve 21 is opened and city water is supplied. Therefore, the first water storage unit is always operated during operation. The water level 17 is higher than the water level detector 19.

  The first exhaust path 8 and the second exhaust path 12 are pipes having sufficiently large inner diameters so that pressure loss does not increase.

  About the fuel cell system 1 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the exhaust port 7 is gradually closed during operation from the state of normal operation shown in FIG. 2A, the pressure loss of the combustion exhaust gas and the oxidant exhaust gas at the exhaust port 7 is reduced as shown in FIG. Since the pressure in the first exhaust path 8 and the second exhaust path 12 increases and the water level of the first water storage part 17 of the water tank 6 decreases. The water stored in the first water storage unit 17 moves to the second water storage unit 18 via the communication unit 6A, so that the water level of the second water storage unit 18 increases by the amount that the water level of the first water storage unit 17 decreases. Then, as shown in FIG. 2C, when the water level of the second water storage unit 18 becomes higher than the drain port 20, the water in the water tank 6 is drained through the drain port 20. When the exhaust port 7 is further blocked, the pressure loss of the combustion exhaust gas and the oxidant exhaust gas at the exhaust port 7 further increases, and the pressures in the first exhaust path 8 and the second exhaust path 12 further increase. As shown to (D), the water level of the 1st water storage part 17 of the water tank 6 becomes still lower, and becomes lower than the lowermost part 16A of the partition 16. Then, the combustion exhaust gas and the oxidant exhaust gas are supplied from the first exhaust passage 8 or the second exhaust passage 12 to the first condensed water passage 9 or the second condensed water passage 13, the first water storage portion 17, the communication portion 6A, and the second water storage water. Since the air bubbles can be discharged from the drain port 20 through the portion 18, even if the exhaust port 7 is blocked, the fuel cell 2 and the hydrogen generator 3 can be prevented from being damaged.

  Even if the exhaust port 7 is blocked, the exhaust gas can be discharged from the drain port 20, but in order to detect that the exhaust port 7 is blocked, the control unit 22 of the fuel cell system 1 in the present embodiment is The water level detector 19 in the second aspect of the present invention has a function of stopping the operation when it detects a drop in the water level during the power generation operation by the fuel cell 2. In the present embodiment, the specified value of the water level sensor 19 is set to the lowermost part of the partition wall 16 so that the water level detector 19 can detect an abnormality in the water level drop when the exhaust port 7 is blocked and the pressure resistance AkPa is lower than the hydrogen generator 3. The position is set to a height equivalent to 16A. For example, if the pressure resistance of the hydrogen generator 3 is lower than the pressure resistance of the fuel cell 2 and the pressure resistance of the hydrogen generator 3 is AkPa, the position 103 × A mm lower than the water level detector drain 20 is set as the specified value of the water level sensor 19. At this time, as shown in FIG. 2B, when the exhaust port 7 is gradually closed, the pressure loss of the combustion exhaust gas and the oxidant exhaust gas at the exhaust port 7 increases, and the first exhaust path 8 and the second exhaust path 12. Therefore, as shown in FIG. 2C, the water level of the first water storage part 17 of the water tank 6 decreases and the water level of the second water storage part 18 increases. When the exhaust port 7 is further closed, as shown in FIG. 2D, the pressure loss of the combustion exhaust gas and the oxidant exhaust gas at the exhaust port 7 further increases, and the pressures of the first exhaust path 8 and the second exhaust path 12 are increased. Is further increased, the water level of the first water storage part 17 of the water tank 6 is lowered to the lowermost part 16A of the partition wall 16, and the combustion exhaust gas and the oxidant exhaust gas become bubbles and pass through the second water storage part 18. On the other hand, the control unit 22 can detect the lowering of the water level of the first water storage unit 17 by the water level sensor 19 and can stop the operation of the fuel cell system 1, and the exhaust port 7 is blocked. In addition, the fuel cell 2 and the hydrogen generator 3 can be prevented from being damaged.

(Embodiment 2)
FIG. 3 is a schematic diagram showing the configuration of the fuel cell system according to Embodiment 2 of the present invention. In FIG. 3, members that are the same as or correspond to those in FIG. 1 are given the same reference numerals, and redundant descriptions are omitted.

  As shown in FIG. 3, the fuel cell system 31 communicates with the water tank 6 in comparison with the fuel cell system 1 shown in FIG. 1 in that the water condensed in the flue gas heat exchanger 5 is guided. Only the condensed water passage 9 is different in that the water condensed in the oxidant exhaust gas heat exchanger 11 is not led to the water tank 6.

  The exhaust port 7 is also different in that it is divided into a first exhaust port 7a for discharging combustion exhaust gas and a second exhaust port 7b for discharging oxidant exhaust gas.

The height of the drain port 20 of the water tank 6 is set so that the exhaust gas can be discharged from the drain port 20 below the pressure resistance of the fuel cell 2 and the hydrogen generator 3 when the exhaust port 7 is closed. Assuming that the height from the lowermost part 16A of the partition wall 16 to the drain outlet 20 is Hmm, the pressure resistance of the hydrogen generator 3 is lower than the pressure resistance of the fuel cell 2, and the pressure resistance of the hydrogen generator 3 is AkPa, from the lowermost part 16A of the partition wall 16 The height H to the drain port 20 is 103 × A mm or less.

  The control unit 22 supplies the raw material blower 4 as a raw material supply unit so that the raw material supply amount detected by the raw material flow meter 32 as the raw material flow rate measurement unit becomes a raw material supply amount corresponding to the generated power as shown in FIG. It is different in that the amount of raw material supply is controlled by changing. For example, the raw material supply amount is 1 NLM at a minimum generated power of 200 W and 4 NLM at a maximum generated power of 1,000 W.

  Moreover, the raw material blower 4 and the raw material flow meter 32 as constituent members in the present embodiment are examples of specific implementations of the raw material supply unit and the raw material flow rate measurement unit in the fourth and fifth aspects of the present invention, respectively.

  About the fuel cell system 31 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. When the exhaust port 7a is gradually closed, the pressure loss of the combustion exhaust gas at the exhaust port 7a increases and the pressure in the first exhaust path 8 increases, so that the water level of the first water reservoir 17 of the water tank 6 decreases. The water level of the second water storage unit 18 rises by the amount that the water level of the first water storage unit 17 is lowered. When the water level of the second water storage unit 18 becomes higher than the drainage port 20, the water level is drained through the drainage port 20. Further, when the exhaust port 7a is closed, the pressure loss of the combustion exhaust gas at the exhaust port 7a further increases and the pressure in the first exhaust path 8 further increases, so that the water level of the first water storage part 17 of the water tank 6 becomes the partition wall. 16 is lower than the lowermost part 16A. Then, similarly to the operation described in FIG. 2, the combustion exhaust gas becomes air bubbles from the first exhaust passage 8 through the first condensed water passage 9, the first water storage portion 17, and the second water storage portion 18, and becomes a drain outlet. Even if the exhaust port 7a is closed, the fuel cell 2 and the hydrogen generator 3 can be prevented from being damaged.

  The control unit 22 of the fuel cell system 31 according to the present embodiment is a specific example in which the control unit 22 stops the operation when the raw material supply amount detected by the raw material flow meter 32 in the third aspect of the present invention falls below a specified value. As a specific example, a prescribed value corresponding to the generated power shown in FIG. 4 is provided. In order to prevent deterioration of the fuel cell 2 due to an increase in the fuel usage rate of the fuel cell 2, the specified value is a raw material supply amount of 0.8 NLM or less, a maximum generated power of 1 with a fuel usage rate of 90% at a minimum generated power of 200 W The raw material supply amount is set to 3.2 NLM or less so that the fuel utilization rate at 90,000 W is 90%, and is set to be a linear line with respect to the generated power. For example, when it is detected that the raw material supply amount detected by the raw material flow meter 32 during the 1,000 W operation has decreased to a predetermined value of 3.2 or less, the control unit 22 stops the operation of the fuel cell system 31.

  At this time, when the exhaust port 7a is gradually closed, the pressure loss of the combustion exhaust gas at the exhaust port 7a increases, the pressure loss of the path including the first exhaust path 8 increases, and the raw material supply amount decreases. At this time, when the raw material supply amount detected by the raw material flow meter 5 falls below a specified value, the control unit 22 can stop the operation of the fuel cell system, and even if the exhaust port 7a is blocked, the fuel cell 2 or It is possible to prevent the hydrogen generator 3 from being damaged.

  In addition, as a specific example of stopping the operation when it is detected that the supply capacity of the raw material blower 4 as the raw material supply unit in the fourth aspect of the present invention is higher than a specified value, the supply capacity of the raw material blower 4 is stopped. Is 80% or more, the pressure resistance of the hydrogen generator 3 is exceeded, and the hydrogen generator may be damaged. Therefore, the specified value of the supply capacity of the raw material blower 4 is set to 70%, which is 10 points lower than 80%. For example, when it is detected that the supply capacity of the raw material blower 4 has increased to a specified value of 70% or more during 1,000 W operation, the control unit 22 stops the operation of the fuel cell system 31.

  When the exhaust port 7a is closed, the pressure loss of the combustion exhaust gas at the exhaust port 7a increases and the pressure in the first exhaust path 8 increases, so that the water level of the first water reservoir 17 of the water tank 6 decreases. At this time, since the pressure loss of the path including the first exhaust path 8 increases, the raw material supply amount decreases. The control unit 22 increases the supply capacity of the raw material blower 4 so that the raw material supply amount detected by the raw material flow meter 32 becomes a raw material supply amount corresponding to the generated power as shown in FIG. When the exhaust port 7 is further blocked, the pressure loss in the path including the first exhaust path 8 further increases, and the supply capacity of the raw material blower 4 further increases. For example, when detecting that the supply capacity of the raw material blower 4 has increased to a specified value of 70% or more during 1,000 W operation, the control unit 22 stops the operation of the fuel cell system 31. Thus, the supply capacity of the raw material blower 4 can detect the blockage of the exhaust port 7a, and even if the exhaust port 7a is blocked, the fuel cell 2 and the hydrogen generator 3 can be prevented from being damaged.

(Embodiment 3)
FIG. 5 is a schematic diagram showing the configuration of the fuel cell system according to Embodiment 3 of the present invention. In FIG. 5, members that are the same as or correspond to those in FIG. 1 are given the same reference numerals, and redundant descriptions are omitted.

  As shown in FIG. 5, the fuel cell system 41 communicates with the water tank 6 in comparison with the fuel cell system 1 shown in FIG. Only the condensed water passage 13 is different in that the water condensed in the combustion exhaust gas heat exchanger 5 is not led to the water tank 6. The exhaust port 7 is also different in that it is divided into a first exhaust port 7a for discharging combustion exhaust gas and a second exhaust port 7b for discharging oxidant exhaust gas. The height of the drain port 20 of the water tank 6 is set so that the exhaust gas can be discharged from the drain port 20 below the pressure resistance of the fuel cell 2 when the exhaust port 7 is closed. Assuming that the height from the lowermost part of the partition wall 16 to the drainage port 20 is Hmm, the pressure resistance of the hydrogen generator 3 is lower than the pressure resistance of the fuel cell 2, and the pressure resistance of the fuel cell 2 is BkPa, The height H is set to 103 × B mm or less.

  The control unit 22 supplies the air blower 10 as an air supply unit so that the air supply amount detected by the air flow meter 42 as the air flow measurement unit becomes an air supply amount according to the generated power as shown in FIG. For example, the air supply amount is 10 NLM for the lowest generated power 200 W and 40 NLM for the highest generated power 1,000 W.

  The air blower 10 and the air flow meter 42 as constituent members in the present embodiment are examples of specific implementations of the air supply unit and the air flow rate measurement unit in the sixth and seventh aspects of the present invention, respectively.

  About the fuel cell system 41 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below. When the exhaust port 7b is closed, the pressure loss of the oxidant exhaust gas at the exhaust port 7b increases and the pressure in the second exhaust path 12 increases, so that the water level of the first water reservoir 17 of the water tank 6 decreases. The water level of the second water storage unit 18 rises by the amount that the water level of the first water storage unit 17 decreases, and when the water level of the second water storage unit 18 becomes higher than the drainage port 20, the water in the water tank 6 passes through the drainage port 20. Drained. Further, when the exhaust port 7b is closed, the pressure loss of the oxidant exhaust gas at the exhaust port 7b further increases, and the water level of the first water reservoir 17 of the water tank 6 becomes lower than that of the partition wall 16. 2, the oxidant exhaust gas becomes bubbles from the second exhaust passage 12 through the second condensate flow path 13, the first water storage section 17, and the second water storage section 18, and drains. Even if the gas can be discharged from the port 20 and the exhaust port 7b is closed, the fuel cell 2 can be prevented from being damaged.

As a specific example, the control unit 22 of the fuel cell system 41 in the present embodiment stops the operation when the air supply amount detected by the air flow meter 42 in the fifth aspect of the present invention falls below a specified value. A prescribed value corresponding to the generated power shown in FIG. 6 is provided. In order to prevent deterioration of the fuel cell 2 due to an increase in the oxidant utilization rate of the fuel cell 2, the specified value is an air supply amount of 6 NLM or less at which the oxidant utilization rate is 80% at the minimum generated power 200 W, and the maximum generated power 1 The oxidant utilization rate at 1,000 W is set to an air supply amount of 24 NLM or less at which the oxidant utilization rate is 80%, and a specified value is set to be a linear line with respect to the generated power. For example, the controller 22 stops the operation of the fuel cell system 41 when detecting that the air supply amount detected by the air flow meter 42 during the 200 W operation has decreased to a specified value of 6 NLM or less.

  At this time, when the exhaust port 7b is gradually closed, the pressure loss of the oxidant exhaust gas at the exhaust port 7b increases, the pressure loss of the air path including the second exhaust channel 12 increases, and the air supply amount decreases. For example, when the control unit 22 detects that the air supply amount detected by the air flow meter 42 during 200 W operation is equal to or less than a specified value of 6 NLM, the operation of the fuel cell system 41 can be stopped, and the exhaust port 7b Even if it is blocked, the fuel cell 2 can be prevented from being damaged.

  Further, as a specific example of stopping the operation when it is detected that the supply capacity of the air blower 10 is higher than a specified value as the air supply unit in the sixth aspect of the present invention, the supply capacity of the air blower 10 is If it is 70% or more, the pressure of the fuel cell 3 becomes higher than the pressure resistance, and the fuel cell 2 may be damaged. Therefore, the specified value of the supply capacity of the air blower 10 is set to 65%, which is 5 points lower than 70%. For example, when it is detected that the supply capacity of the air blower 10 has increased to a specified value of 65% or more during 200 W operation, the control unit 22 stops the operation of the fuel cell system 41.

  When the exhaust port 7b is gradually closed, the pressure loss of the oxidant exhaust gas at the exhaust port 7b increases and the pressure in the second exhaust path 12 increases, so that the water level of the first water reservoir 17 of the water tank 6 decreases. . At this time, the pressure loss of the air path including the second exhaust path 12 increases, and the air supply amount decreases. The controller 22 increases the supply capacity of the air blower 10 so that the air supply amount detected by the air flow meter 42 becomes an air supply amount corresponding to the generated power as shown in FIG. Further, when the exhaust port 7b is blocked, the pressure loss in the air path further increases. For example, when detecting that the supply capacity of the air blower 4 has increased to a specified value of 65% or more during 1,000 W operation, the control unit 22 can stop the operation of the fuel cell system 41, and the exhaust port 7b. Even if the fuel cell is blocked, the fuel cell 2 can be prevented from being damaged.

  The fuel cell system of the present invention is useful for, for example, a fuel cell system used for a cogeneration apparatus.

DESCRIPTION OF SYMBOLS 1, 31, 41, 201 Fuel cell system 2, 202 Fuel cell 3, 203 Hydrogen generator 3a, 203a Combustor 4, 204 Raw material blower 5, 205 Combustion exhaust gas heat exchanger 6, 206 Water tank 7, 207 Exhaust port 7a Combustion exhaust gas exhaust port 7b Oxidant exhaust gas exhaust port 8, 208 First exhaust channel 9, 209 First condensate channel 10, 210 Air blower 11, 211 Oxidant exhaust gas heat exchanger 12, 212 Second exhaust channel 13, 213 Second Condensate channel 14 Hot water storage tank 15 Hot water circulation channel 16 Bulkhead 17 First reservoir 18 Second reservoir 19 Water level detector 20 Drain port 21 Water supply valve 22 Control unit 32 Raw material flow meter 42 Air flow meter

Claims (6)

A hydrogen generator that generates hydrogen-containing fuel gas from a raw material and water by a reforming reaction; a fuel cell that generates electricity using the fuel gas and an oxidant gas that includes oxygen; and the hydrogen generator and the fuel cell. An exhaust port that exhausts exhaust gas exhausted from at least one of the casings, a first flow path that guides the exhaust gas to the exhaust port, and water that is contained in the exhaust gas is stored in a sealed casing. A water tank; and a second flow path that branches from the first flow path and guides the water contained in the exhaust gas to the water tank. The water tank includes a first water storage section and a second water storage section. A partition wall to be divided, a communication portion that communicates water stored in the first water storage portion and the second water storage portion, and a second flow path that communicates with the first water storage portion are provided. The part is higher than the lowest part of the partition wall and higher than the communication part Fuel cell system, characterized in that it constitutes a drain port which is disposed. The water tank has a water level detector for detecting the water level, and is controlled so that the operation is stopped when the water level detector detects that the water level is lower than a specified value provided at a position higher than the communication portion. The fuel cell system according to claim 1, further comprising a control unit that performs the operation. A raw material supply unit that supplies a raw material gas to the hydrogen generator and a raw material flow rate measurement unit that measures a raw material supply amount supplied from the raw material supply unit, and operates when the raw material supply amount falls below a specified value The fuel cell system according to claim 1, further comprising a control unit that controls to stop the operation. And a control unit that controls to stop the operation when detecting that the supply capacity of the raw material supply unit is higher than a specified value. The fuel cell system according to claim 1, wherein the fuel cell system is provided. An air supply unit that supplies air to the fuel cell and an air flow rate measurement unit that measures an air supply amount supplied from the air supply unit, and stops operation when the air supply amount falls below a specified value The fuel cell system according to claim 1, further comprising a control unit configured to perform control. An air supply unit that supplies air to the fuel cell; and a control unit that controls to stop the operation when detecting that the supply capability of the air supply unit is higher than a specified value. The fuel cell system according to claim 1.